This invention relates to orbiting mass vibrators, and in particular, to orbiting mass vibrators adapted for use on a rotary-vibratory drills or sonic drills.
In conventional orbiting mass vibrators adapted for use on rotary-vibratory drills, vibratory energy is generated by a pair of counter-rotating eccentric masses rotating along confined orbital paths within a housing. The eccentric masses are confined to the orbital paths by a cylindrical bore in the housing. Each eccentric mass is coupled to the housing and delivers vibratory forces to the housing. The housing in turn provides the vibratory output to a drill bit. However, if the eccentric masses and crankshafts are not properly aligned, excess vibratory forces may develop in the crankshafts. These excess vibratory forces may ultimately cause damage to the rotary-vibratory apparatus. It is therefore an objective of the invention to provide a self compensating mechanism which allows the eccentric masses and crankshafts to remain decoupled during the operation of the rotary-vibratory apparatus.